释义 |
直肠zhícháng大肠的最末段,上端与乙状结肠相连,下端与肛门相连,作用是吸收水分。当粪便到达直肠时,直肠收缩,肛门周围的括约肌张开,粪便就从肛门排出。{rectum; lower part of the alimentary canal, between the sigmoid flexure and the anus, whose function is to absorb water. When excrement reaches the rectum, the rectum contracts and the sphincter of the anus dilates so as to discharge the excrement.} |